Secondhand smoke (SHS) is recognized as a class A carcinogen and has no safe level of exposure. SHS is estimated to contribute to over 3,000 lung cancer deaths in non-smokers annually. With widespread legislation restricting smoking in workplaces and other public venues, most of the U.S. public now live in states with laws to protect against SHS exposure. Yet, the primary place in which involuntary exposure to SHS still occurs is now in homes. Nonsmokers from the Cheyenne River Sioux Tribe, a Lakota tribe from South Dakota, disproportionately share the burden of SHS, especially in their homes. Our own recent findings show that Cheyenne River Sioux adult nonsmokers have cotinine levels equal to those regularly seen in active smokers. With smoking prevalence as high as 50% among this population, the consequences of SHS already manifest in this Tribe, including high prevalences of childhood asthma and sudden infant death syndrome. Further complicating matters, the expanded use of commercial tobacco products for ceremonial and cultural practices is creating challenges not typically seen in non-American Indian communities. Therefore, eliminating SHS exposure in a culturally appropriate manner is a fundamental step in decreasing morbidity and mortality among Cheyenne River Sioux Tribe and other Northern Plains Tribes. Our primary study objective is to test a culturally tailored intervention to encourage adoption of home smoking restrictions in Cheyenne River Sioux Tribal households where nonsmokers are present. We propose to conduct a randomized, controlled trial to develop, implement and evaluate a culturally tailored SHS advocacy training both with and without urinary biomarker feedback. Biomarker feedback is an intervention method that provides highly personalized feedback including, in this instance, levels of urinary tobacco-specific pro-carcinogen markers that further characterize evidence of the negative sequelae of smoking in homes Our Specific Aims are to 1) Assess knowledge, attitudes and beliefs about secondhand smoke exposure and perceived barriers to adoption of smoking restrictions in tribal member households on the Cheyenne River Sioux Tribe Reservation. Based on our prior work we expect that few participants know about the dangers associated with SHS exposure. We expect that few have smoke-free homes; 2) Augment, implement, and evaluate a nonsmokers? urinary cotinine and carcinogen biomarker feedback intervention on the adoption of household smoking restrictions. We expect that the nonsmoker adults who receive advocacy training with urinary biomarker feedback will be more likely to affirm that smoking restrictions are needed within their households than those just receiving advocacy training only, and; 3) Determine the effect of the intervention on health-related quality of life 6 months after implementation of advocacy and biomarker feedback intervention. We hypothesize that the intervention will be associated with improved health-related quality of life, beyond any improvement experienced by advocacy training-only control group.